Some dynamically-typed languages (e.g., JavaScript) provide computational objects in the form of associative arrays. An associative array is an abstract data structure arranges as a collection of key-value pairs, such that each possible key appears at most once in the collection. Accordingly, property values may be stored and looked up by referencing a key. For example, a lookup may be performed based on a property name to locate a pointer to a memory location of the value. To facilitate a faster determination of the memory location, dynamically-typed languages dynamically generate object maps for computational objects at runtime to describe the memory layout of the objects. Additionally, in a dynamically-typed language, the type of a property value is often not known until runtime, and program code loaded during runtime may invalidate a prior assumption about the type of property value. This makes it difficult for a language implementation to use a “raw” storage format for double values.